The easterly wave progression is vivid.
The low in the lower latitude [10 DEG North] is oscillated in the progress of easterly wave.
Since it is wave type propagation only NON convective clouds are predominant. The movement is tossed by troughs & crusts. [(Alternate) west-east shift of cloud formation and east to west dissipation of cloud band] This will persist for another 48 hours.
This will enhance the rainfall for Chennai city.
The cold easterly trough brought day time cold in north coastal Tamil Nadu ,especially at Chennai, and the stratus clouds gave moderate to heavy rainfall.
The crest in the west will be moisturized to give [dense] fog in North western parts of TamilNadu